A method of rehabilitating an existing pipe is known. This method includes providing a rehabilitating pipe in an existing pipe, such as a sewage pipe. The rehabilitating pipe has an outer diameter that is somewhat smaller than the inner diameter of the existing pipe. The method further includes filling a space between the outer circumference of the rehabilitating pipe and the inner wall surface of the existing pipe with a filling material and curing the filling material to build a composite pipe. The existing pipe can thus be repaired or renovated. In the existing pipe renovation work, the position of the rehabilitating pipe may usually be adjusted from side to side and up and down in the existing pipe, and the rehabilitating pipe may have to be positioned and fixed to a position at which the rehabilitating pipe is shifted somewhat downward from the concentric position with the existing pipe and the lower end of outer circumference of the rehabilitating pipe is in the contact with the pipe bottom of the existing pipe.
This is because the pipe bottom of the rehabilitating pipe should come close to the pipe bottom of the existing pipe as much as possible to ensure the flow of a fluid in the existing pipe and also because damage of the existing pipe largely occurs at the upper portion thereof and the filling material should have a large thickness at the upper portion to enhance the strength. However, the rehabilitating pipe may be made of a plastic material of which the specific gravity is smaller than that of the filling agent, and the rehabilitating pipe will float on the filling agent. Therefore, positioning of the rehabilitating pipe may have to be performed as the above such that the rehabilitating pipe is pushed down to a certain position.
For the purpose of such positioning of the rehabilitating pipe, a method has conventionally been employed in which a rectangular material processed to be a spacer having a necessary height (thickness) is inserted and interposed between the outer circumference of the rehabilitating pipe and the inner wall surface of the existing pipe. In addition, Patent Document 1 discloses a spacer comprising: a first wedge-like member configured to be slanted at a certain angle such that the height increases as the position comes close to the back side in the insertion direction; and a second wedge-like member configured to be slanted at the same angle as the slant angle of the first wedge-like member and to lay on the first wedge-like member such that the slanted surfaces are in contact with each other.